where \(W_{10}\)  is the pulse width measured at 10% of the peak flux (e.g. [1]}).
Furthermore, relativistic effects are important due to the rapid rotation of the magnetosphere as initially discussed in [2]}. They showed that the location of the inflection point of the PA swing is delayed with respect to the centre of the pulse profile by an amount given by
\(\Delta _\phi = \frac{8\,\,\, \pi \,\,\, h_{\rm em}}{P\,\,\, c}\) 
